片外FLASH 读取函数

//****************************   Read Data    *****************************
unsigned int ReadData(unsigned int addr,unsigned char *data,unsigned int n)
{ 
unsigned char *a, temp;

a = (unsigned char*)&addr;

SPIBR = 0x11;
SPICR2 = 0x0d;         //enable cs0;
SPICR1 |= 0x80;

while(!(SPISR & 0x02));
SPIDR = 0x03;
for(i = 1; i < 4; i++) 
{
while(!(SPISR & 0x02));
SPIDR = a[i]; //use SPI 4-level FIFO
}

while(!(SPISR & 0x20)); //发送未完成死循环
    //temp = SPIDR; //这个是不是错误的先注释
SPICR4 |=0x80; //同时清空发送FIFO和接收FIFO

delay_ms_spi(100);

for(i=0;i {
delay_ms_spi(10);

/////////////****************************************************大爷的这两句不能注释，注释后为错
while(!(SPISR & 0x02)); //发送FIFO满死循环*******************初步怀疑为预读先写 不过DataSheet中并没有明确表明！！！
SPIDR = 0x00;
/////////////****************************************************大爷的这两句不能注释，注释后为错

while(!(SPISR & 0x04)); //接收FIFO空死循环
        *data = SPIDR;
data++;

delay_ms_spi(10);
}
 
SPICR4 |=0x80; //同时清空发送FIFO和接收FIFO
   
SPICR2 = 0x0c; //disable cs0
}